The present invention relates to derivatives of phenylacetic ester, represented by the formula (I): ##STR3## wherein R.sup.1 represents a halogen atom or a lower alkoxy group; R.sup.2 represents a lower alkyl group; R.sup.3 represents a hydrogen atom or a methyl group; R.sup.4 represents a hydrogen atom, a lower alkyl group, ##STR4## and R.sup.5 represents a hydrogen atom or a halogen atom, a process for producing the derivatives and an insecticidal composition containing at least one of the derivatives of phenylacetic ester represented by the formula (I) as an active ingredient.
Although many insecticidally active compounds have been hitherto known, of these compounds, natural pyrethrins and their analogous compounds have been broadly used for controlling noxious insects in sanitation, agriculture and horticulture because of their excellent insecticidal activity as well as the swift activity to noxious insects, the low toxicity to human and animal and the fact that they hardly cause insecticide-resistance in insect species to which the insecticides are applied.
However, since natural pyrethrins are so high in price, it is difficult economically to use natural pyrethrins or their analogous compounds such as allethrin broadly in various fields. In order to dissolve the demerit, many compounds have been synthesized. However, at present a larger part of the thus synthesized compounds are inferior to natural pyrethrins and allethrin in the insecticidal activity and the economical efficiency.
As a result of study for a novel and easily synthesizable insecticidal compound, the present inventors have found that the derivatives of phenylacetic ester represented by the formula (I) has excellent insecticidal properties, more swifter insecticidal activity as compared with allethrin and a reliable lethality to insect which has been quite insufficient in allethrin, and based on the finding, the present inventors have completed the present invention.